The present invention to relates to a toggle retainer for toggle connections of conveyor pans for chain scraper conveyors, guide pans of mining machine conveyors etc, with a securing plate which engages across one of the locking extensions of a toggle and secures it in the accepting pocket and both ends of which can be inserted into an associated insertion pocket and retained therein by means of securing component which engages through a locking opening arranged in the insertion pocket and an accepting hole in the securing plate.
The chain scraper conveyors used in underground mining operations comprise individual conveyor pans which are joined together using toggle connections which are able to withstand tension and are movable within limits against each other so that the chain scraper conveyor can be moved in sections even with unevenness of the ground. The toggles (dog bones) are inserted here in accepting pockets, which are open at the side and are secured in them against falling out at the side using a toggle retaining device. The toggles employed by the DBT GmbH and widely distributed in the market have an extended bolt head with flat locking extensions at the axial ends of the toggle, which are engaged across by a removable securing plate. In the assembled condition and the secured condition, the securing plate engages at both ends in an associated insertion pocket and is secured in a locking hole in or on the insertion pocket by means of a securing device. Toggle connections are, in any case, not only applied in chain scraper conveyors but also for the connection of mining machine guide troughs hooked together in sections such as plough or plough chain guides.
A previously proposed toggle securing method is described in DE 295 02 953, in which the securing plate has a driving hole for a tensioning sleeve on one end and at its other end a driving hole for a plastics material pin with which it is retained in the locking hole of the insertion pocket. From DE 100 11 288 U1 a toggle securing device for toggle connections is known in which two securing means are formed from detachable deformable plastics material bolts, which can be inserted, into the locking openings. This offers the advantage of a very simple and fast assembly and disassembly. A disadvantage is however that the plastics material bolts can tear with excessive loading due to the unavoidable vibrations occurring in underground applications.
It is the aim of the present invention to produce an improved and cost-effective toggle retaining method, which is easily handled, and which secures the toggle reliably in the locking position and against falling out.
Accordingly the present invention is directed to a toggle retainer as described in the opening paragraph of the present specifications in which the securing means have a sleeve-like deformable outer part especially of plastics material, which is provided with a reinforcing core of harder material especially a reinforcement core of metal. By the combination of an outer part which is deformable and of low stiffness with a reinforcing core of higher stiffness, a cost-effective securing means is produced which can accept all the loading especially vibration with reduced risk of failing and nevertheless due to the deformable outer part can easily and quickly be assembled and disassembled.
According to a preferred embodiment the reinforcing core comprises a clamping sleeve. Alternatively the reinforcing core can comprise a rod of solid material. In both configurations it is advantageous if the clamping sleeve or the rod comprises rust-free steel so that the reinforcing core can withstand the underground environmental conditions, especially the damp climate. Advantageously two securing means are constructed in the same manner are provided so that the required stores holding for the securing means is simplified and minimised.
As is proposed in DE 100 11 288, it is preferable if in the toggle securing method according to the present invention both of the locking openings associated with the insertion pockets are made as open edge lock cut outs. Advantageously the accepting holes of the securing plate provided are on at least one securing plate side, preferably both sides, with a depression whose opening angle xcex1 amounts preferably to 120xc2x0. A suitably large free angle ensures that no briquetting arises between the securing means and the securing plate from coal dust or similar. Preferably the upper side of the securing plate is provided on the sides with preferably wedge shaped inclines. Both of the previously quoted measures operate against the frequently observed briquetting of coal dust in underground applications when mining coal. Apart from this these measures support the fast and problem free exchange of the pans or guiding troughs in the event of wear owing to the easier disassembly of the toggle securing and the toggle bolts.
With the toggle securing measures according to the present invention, the assembly and disassembly of the securing plate is effected for instance in that a securing plate with pre-assembled retention means is assembled onto one of the edge-open locking openings, whereby the securing plate is then pivoted using elastic deformation both of the securing means in the one locking cut out and also of the other securing means so that its free end is inserted into the locking opening of the other insertion pocket. To make this pivoting in easier, the securing plate in a preferred embodiment is configured with between the accepting holes a multi-angled disassembly opening is formed for the engagement of a disassembly tool. It is especially preferred if the disassembly opening is square and matched to the standard cross section of a ratchet tool drive head. The disassembly hole can especially be a square hole with a nominal size of 21 mm.